CVE-2025-22035

Technical Description

In the Linux kernel, the following vulnerability has been resolved:

tracing: Fix use-after-free in print_graph_function_flags during tracer switching

Kairui reported a UAF issue in print_graph_function_flags() during

ftrace stress testing [1]. This issue can be reproduced if puting a

'mdelay(10)' after 'mutex_unlock(&trace_types_lock)' in s_start(),

and executing the following script:

$ echo function_graph > current_tracer

$ cat trace > /dev/null &

$ sleep 5 # Ensure the 'cat' reaches the 'mdelay(10)' point

$ echo timerlat > current_tracer

The root cause lies in the two calls to print_graph_function_flags

within print_trace_line during each s_show():

* One through 'iter->trace->print_line()';

* Another through 'event->funcs->trace()', which is hidden in

print_trace_fmt() before print_trace_line returns.

Tracer switching only updates the former, while the latter continues

to use the print_line function of the old tracer, which in the script

above is print_graph_fu

Remediation

Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Affected Products

References